package unionfind;

/**
 * @Description
 * @Author zhout
 * @Date 2019/1/30 11:44
 **/
//我们第一版Union-Find
public class UnionFind1 implements UF {

    private int[] id;

    public  UnionFind1(int size){
        id = new int[size];
        for(int i = 0; i < id.length ;i++){
            id[i] = i;
        }
    }
    @Override
    public int getSize() {
        return id.length;
    }

    //查找元素p对应集合的编号
    private int find(int p){
        if(p < 0 || p >= id.length){
            throw new IllegalArgumentException("p is out of range");
        }
        return id[p];
    }

    //查看元素p和元素q是否在同一个集合
    @Override
    public boolean isConnected(int p, int q) {
        return find(p) == find(q);
    }

    //合并元素p和元素q所属的集合
    @Override
    public void unionElements(int p, int q) {
        int pID = find(p);
        int qID = find(q);

        if(pID == qID){
            return;
        }

        for(int i = 0; i < id.length; i++){
            if(id[i] == pID){
                id[i] = qID;
            }
        }
    }
}
